Greater Scaup
(Aythya marila)

Overview

Summary

© Ralph Hocken
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Two Scaup species occur in Canada, the Greater Scaup and the Lesser Scaup. These two closely related species are nearly identical in appearance, which can cause difficulties in distinguishing them. The population status of Scaup in North America became a conservation concern due to apparent declines from historic high levels observed in the late 1970s. Their populations have not yet fully recovered, and research to understand the cause of the decline is ongoing. Greater Scaup are the least abundant of the two species and are the only diving duck with a circumpolar breeding distribution. It is widely distributed across Arctic and Subarctic regions where it mainly nests in coastal tundra habitats. The information below regarding the population estimate and population status is for the two species combined. This species has been identified as a priority for conservation and/or stewardship in one or more Bird Conservation Region Strategies in Canada.

Designations

Population status

Distribution maps

• BirdLife International / NatureServe
• North American Breeding Bird Survey (BBS): Relative Abundance and Breeding Distribution (1970-2016)

Migration strategy, occurrence

Responsibility for conservation

General nesting period in Canada

Conservation and management

As it is very difficult to differentiate between Greater Scaup and Lesser Scaup during aerial surveys and most ground-based surveys, species-specific population estimates and population trends cannot be obtained. Because Lesser Scaup are a dominant component of the combined population, changes in population status of the less abundant Greater Scaup may be undetectable. Research is ongoing to understand why Scaup have declined during the drought years in the 1980s (similarly to other ducks), but were slow to recover when habitat conditions improved subsequently (Austin et al. 2000, Anteau et al. 2014). The harvest of Scaup has declined considerably in Canada over the long-term.

Bird conservation region strategies

Environment and Climate Change Canada and partners have developed Bird Conservation Region Strategies in each of Canada’s Bird Conservation Regions (BCRs). In these strategies, selected species are identified as priorities for one or more of the following reasons:

• conservation concerns (i.e., species vulnerable due to population size, distribution, population trend, abundance, or threats)
• stewardship responsibilities (i.e., species that typify the regional avifauna or have a large proportion of their range or population in the sub-region)
• management concerns (i.e., species that require ongoing management because of their socio-economic importance as game species, or because of their impacts on other species or habitats)
• other concerns (i.e., species deemed a priority by regional experts for other reasons than those listed above or because they are listed as species at risk or concern at the provincial level)

Select any of the sub-regions below to view the BCR strategy for additional details.

References

• Anteau, M.J., J.-M.K. DeVink, N. David, J.E. Austin, C.M. Custer, and A.D. Afton. 2014. Lesser Scaup (Aythya affinis), version 2.0. In: The Birds of North America (P.G. Rodewald, ed.). Cornell Lab of Ornithology, Ithaca, New York, USA. Anteau, M.J., J.-M.K. DeVink, N. David, J.E. Austin, C.M. Custer, and A.D. Afton. 2014. Lesser Scaup (Aythya affinis), version 2.0. In: The Birds of North America (P.G. Rodewald, ed.). Cornell Lab of Ornithology, Ithaca, New York, USA. (Link)
• Austin, J.E., A.D. Afton, M.G. Anderson, R.G. Clark, C.M. Custer, J.S. Lawrence, J.B. Pollard, and J.K. Ringelman. 2000. Declining Scaup Populations: Issues, Hypotheses, and Research Needs. Wildlife Society Bulletin 28: 254–263.
• Canadian Wildlife Service (CWS) Waterfowl Committee. 2017. Population Status of Migratory Game Birds in Canada: November 2017. CWS Migratory Birds Regulatory Report Number 49. 221 pp. Canadian Wildlife Service (CWS) Waterfowl Committee. 2017. Population Status of Migratory Game Birds in Canada: November 2017. CWS Migratory Birds Regulatory Report Number 49. 221 pp. (Link)